| No | Pattern | Freq | Relations |
|---|---|---|---|
| 1 | [prep] a [adv] long period of | 12 |
|
| 2 | [prep] a [adv] long period of | 12 |
|
| 3 | over a [adv] [adj] period of | 8 |
|
| 4 | over a [adv] long [noun sg] of | 5 |
|
| 5 | over a [adv] long period [prep] | 5 |
|
| 6 | over a [adv] long period of | 5 |
|
| 7 | over a [adv] long period of | 5 |
|
| 8 | over a [adv] long period [prep] | 5 |
|
| 9 | over [art] [adv] long period of | 5 |
|
| 10 | over a [adv] long [noun] of | 5 |
|
| 11 | over a [adv] long period of | 5 |
|
| 12 | over a [adv] long period of | 5 |
|
